xref: /openbmc/linux/net/ipv6/udp.c (revision 206a81c1)
1 /*
2  *	UDP over IPv6
3  *	Linux INET6 implementation
4  *
5  *	Authors:
6  *	Pedro Roque		<roque@di.fc.ul.pt>
7  *
8  *	Based on linux/ipv4/udp.c
9  *
10  *	Fixes:
11  *	Hideaki YOSHIFUJI	:	sin6_scope_id support
12  *	YOSHIFUJI Hideaki @USAGI and:	Support IPV6_V6ONLY socket option, which
13  *	Alexey Kuznetsov		allow both IPv4 and IPv6 sockets to bind
14  *					a single port at the same time.
15  *      Kazunori MIYAZAWA @USAGI:       change process style to use ip6_append_data
16  *      YOSHIFUJI Hideaki @USAGI:	convert /proc/net/udp6 to seq_file.
17  *
18  *	This program is free software; you can redistribute it and/or
19  *      modify it under the terms of the GNU General Public License
20  *      as published by the Free Software Foundation; either version
21  *      2 of the License, or (at your option) any later version.
22  */
23 
24 #include <linux/errno.h>
25 #include <linux/types.h>
26 #include <linux/socket.h>
27 #include <linux/sockios.h>
28 #include <linux/net.h>
29 #include <linux/in6.h>
30 #include <linux/netdevice.h>
31 #include <linux/if_arp.h>
32 #include <linux/ipv6.h>
33 #include <linux/icmpv6.h>
34 #include <linux/init.h>
35 #include <linux/module.h>
36 #include <linux/skbuff.h>
37 #include <linux/slab.h>
38 #include <asm/uaccess.h>
39 
40 #include <net/ndisc.h>
41 #include <net/protocol.h>
42 #include <net/transp_v6.h>
43 #include <net/ip6_route.h>
44 #include <net/raw.h>
45 #include <net/tcp_states.h>
46 #include <net/ip6_checksum.h>
47 #include <net/xfrm.h>
48 #include <net/inet6_hashtables.h>
49 #include <net/busy_poll.h>
50 
51 #include <linux/proc_fs.h>
52 #include <linux/seq_file.h>
53 #include <trace/events/skb.h>
54 #include "udp_impl.h"
55 
56 static unsigned int udp6_ehashfn(struct net *net,
57 				  const struct in6_addr *laddr,
58 				  const u16 lport,
59 				  const struct in6_addr *faddr,
60 				  const __be16 fport)
61 {
62 	static u32 udp6_ehash_secret __read_mostly;
63 	static u32 udp_ipv6_hash_secret __read_mostly;
64 
65 	u32 lhash, fhash;
66 
67 	net_get_random_once(&udp6_ehash_secret,
68 			    sizeof(udp6_ehash_secret));
69 	net_get_random_once(&udp_ipv6_hash_secret,
70 			    sizeof(udp_ipv6_hash_secret));
71 
72 	lhash = (__force u32)laddr->s6_addr32[3];
73 	fhash = __ipv6_addr_jhash(faddr, udp_ipv6_hash_secret);
74 
75 	return __inet6_ehashfn(lhash, lport, fhash, fport,
76 			       udp_ipv6_hash_secret + net_hash_mix(net));
77 }
78 
79 int ipv6_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2)
80 {
81 	const struct in6_addr *sk2_rcv_saddr6 = inet6_rcv_saddr(sk2);
82 	int sk_ipv6only = ipv6_only_sock(sk);
83 	int sk2_ipv6only = inet_v6_ipv6only(sk2);
84 	int addr_type = ipv6_addr_type(&sk->sk_v6_rcv_saddr);
85 	int addr_type2 = sk2_rcv_saddr6 ? ipv6_addr_type(sk2_rcv_saddr6) : IPV6_ADDR_MAPPED;
86 
87 	/* if both are mapped, treat as IPv4 */
88 	if (addr_type == IPV6_ADDR_MAPPED && addr_type2 == IPV6_ADDR_MAPPED)
89 		return (!sk2_ipv6only &&
90 			(!sk->sk_rcv_saddr || !sk2->sk_rcv_saddr ||
91 			  sk->sk_rcv_saddr == sk2->sk_rcv_saddr));
92 
93 	if (addr_type2 == IPV6_ADDR_ANY &&
94 	    !(sk2_ipv6only && addr_type == IPV6_ADDR_MAPPED))
95 		return 1;
96 
97 	if (addr_type == IPV6_ADDR_ANY &&
98 	    !(sk_ipv6only && addr_type2 == IPV6_ADDR_MAPPED))
99 		return 1;
100 
101 	if (sk2_rcv_saddr6 &&
102 	    ipv6_addr_equal(&sk->sk_v6_rcv_saddr, sk2_rcv_saddr6))
103 		return 1;
104 
105 	return 0;
106 }
107 
108 static unsigned int udp6_portaddr_hash(struct net *net,
109 				       const struct in6_addr *addr6,
110 				       unsigned int port)
111 {
112 	unsigned int hash, mix = net_hash_mix(net);
113 
114 	if (ipv6_addr_any(addr6))
115 		hash = jhash_1word(0, mix);
116 	else if (ipv6_addr_v4mapped(addr6))
117 		hash = jhash_1word((__force u32)addr6->s6_addr32[3], mix);
118 	else
119 		hash = jhash2((__force u32 *)addr6->s6_addr32, 4, mix);
120 
121 	return hash ^ port;
122 }
123 
124 
125 int udp_v6_get_port(struct sock *sk, unsigned short snum)
126 {
127 	unsigned int hash2_nulladdr =
128 		udp6_portaddr_hash(sock_net(sk), &in6addr_any, snum);
129 	unsigned int hash2_partial =
130 		udp6_portaddr_hash(sock_net(sk), &sk->sk_v6_rcv_saddr, 0);
131 
132 	/* precompute partial secondary hash */
133 	udp_sk(sk)->udp_portaddr_hash = hash2_partial;
134 	return udp_lib_get_port(sk, snum, ipv6_rcv_saddr_equal, hash2_nulladdr);
135 }
136 
137 static void udp_v6_rehash(struct sock *sk)
138 {
139 	u16 new_hash = udp6_portaddr_hash(sock_net(sk),
140 					  &sk->sk_v6_rcv_saddr,
141 					  inet_sk(sk)->inet_num);
142 
143 	udp_lib_rehash(sk, new_hash);
144 }
145 
146 static inline int compute_score(struct sock *sk, struct net *net,
147 				unsigned short hnum,
148 				const struct in6_addr *saddr, __be16 sport,
149 				const struct in6_addr *daddr, __be16 dport,
150 				int dif)
151 {
152 	int score = -1;
153 
154 	if (net_eq(sock_net(sk), net) && udp_sk(sk)->udp_port_hash == hnum &&
155 			sk->sk_family == PF_INET6) {
156 		struct inet_sock *inet = inet_sk(sk);
157 
158 		score = 0;
159 		if (inet->inet_dport) {
160 			if (inet->inet_dport != sport)
161 				return -1;
162 			score++;
163 		}
164 		if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr)) {
165 			if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr))
166 				return -1;
167 			score++;
168 		}
169 		if (!ipv6_addr_any(&sk->sk_v6_daddr)) {
170 			if (!ipv6_addr_equal(&sk->sk_v6_daddr, saddr))
171 				return -1;
172 			score++;
173 		}
174 		if (sk->sk_bound_dev_if) {
175 			if (sk->sk_bound_dev_if != dif)
176 				return -1;
177 			score++;
178 		}
179 	}
180 	return score;
181 }
182 
183 #define SCORE2_MAX (1 + 1 + 1)
184 static inline int compute_score2(struct sock *sk, struct net *net,
185 				const struct in6_addr *saddr, __be16 sport,
186 				const struct in6_addr *daddr, unsigned short hnum,
187 				int dif)
188 {
189 	int score = -1;
190 
191 	if (net_eq(sock_net(sk), net) && udp_sk(sk)->udp_port_hash == hnum &&
192 			sk->sk_family == PF_INET6) {
193 		struct inet_sock *inet = inet_sk(sk);
194 
195 		if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr))
196 			return -1;
197 		score = 0;
198 		if (inet->inet_dport) {
199 			if (inet->inet_dport != sport)
200 				return -1;
201 			score++;
202 		}
203 		if (!ipv6_addr_any(&sk->sk_v6_daddr)) {
204 			if (!ipv6_addr_equal(&sk->sk_v6_daddr, saddr))
205 				return -1;
206 			score++;
207 		}
208 		if (sk->sk_bound_dev_if) {
209 			if (sk->sk_bound_dev_if != dif)
210 				return -1;
211 			score++;
212 		}
213 	}
214 	return score;
215 }
216 
217 
218 /* called with read_rcu_lock() */
219 static struct sock *udp6_lib_lookup2(struct net *net,
220 		const struct in6_addr *saddr, __be16 sport,
221 		const struct in6_addr *daddr, unsigned int hnum, int dif,
222 		struct udp_hslot *hslot2, unsigned int slot2)
223 {
224 	struct sock *sk, *result;
225 	struct hlist_nulls_node *node;
226 	int score, badness, matches = 0, reuseport = 0;
227 	u32 hash = 0;
228 
229 begin:
230 	result = NULL;
231 	badness = -1;
232 	udp_portaddr_for_each_entry_rcu(sk, node, &hslot2->head) {
233 		score = compute_score2(sk, net, saddr, sport,
234 				      daddr, hnum, dif);
235 		if (score > badness) {
236 			result = sk;
237 			badness = score;
238 			reuseport = sk->sk_reuseport;
239 			if (reuseport) {
240 				hash = udp6_ehashfn(net, daddr, hnum,
241 						    saddr, sport);
242 				matches = 1;
243 			} else if (score == SCORE2_MAX)
244 				goto exact_match;
245 		} else if (score == badness && reuseport) {
246 			matches++;
247 			if (((u64)hash * matches) >> 32 == 0)
248 				result = sk;
249 			hash = next_pseudo_random32(hash);
250 		}
251 	}
252 	/*
253 	 * if the nulls value we got at the end of this lookup is
254 	 * not the expected one, we must restart lookup.
255 	 * We probably met an item that was moved to another chain.
256 	 */
257 	if (get_nulls_value(node) != slot2)
258 		goto begin;
259 
260 	if (result) {
261 exact_match:
262 		if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
263 			result = NULL;
264 		else if (unlikely(compute_score2(result, net, saddr, sport,
265 				  daddr, hnum, dif) < badness)) {
266 			sock_put(result);
267 			goto begin;
268 		}
269 	}
270 	return result;
271 }
272 
273 struct sock *__udp6_lib_lookup(struct net *net,
274 				      const struct in6_addr *saddr, __be16 sport,
275 				      const struct in6_addr *daddr, __be16 dport,
276 				      int dif, struct udp_table *udptable)
277 {
278 	struct sock *sk, *result;
279 	struct hlist_nulls_node *node;
280 	unsigned short hnum = ntohs(dport);
281 	unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask);
282 	struct udp_hslot *hslot2, *hslot = &udptable->hash[slot];
283 	int score, badness, matches = 0, reuseport = 0;
284 	u32 hash = 0;
285 
286 	rcu_read_lock();
287 	if (hslot->count > 10) {
288 		hash2 = udp6_portaddr_hash(net, daddr, hnum);
289 		slot2 = hash2 & udptable->mask;
290 		hslot2 = &udptable->hash2[slot2];
291 		if (hslot->count < hslot2->count)
292 			goto begin;
293 
294 		result = udp6_lib_lookup2(net, saddr, sport,
295 					  daddr, hnum, dif,
296 					  hslot2, slot2);
297 		if (!result) {
298 			hash2 = udp6_portaddr_hash(net, &in6addr_any, hnum);
299 			slot2 = hash2 & udptable->mask;
300 			hslot2 = &udptable->hash2[slot2];
301 			if (hslot->count < hslot2->count)
302 				goto begin;
303 
304 			result = udp6_lib_lookup2(net, saddr, sport,
305 						  &in6addr_any, hnum, dif,
306 						  hslot2, slot2);
307 		}
308 		rcu_read_unlock();
309 		return result;
310 	}
311 begin:
312 	result = NULL;
313 	badness = -1;
314 	sk_nulls_for_each_rcu(sk, node, &hslot->head) {
315 		score = compute_score(sk, net, hnum, saddr, sport, daddr, dport, dif);
316 		if (score > badness) {
317 			result = sk;
318 			badness = score;
319 			reuseport = sk->sk_reuseport;
320 			if (reuseport) {
321 				hash = udp6_ehashfn(net, daddr, hnum,
322 						    saddr, sport);
323 				matches = 1;
324 			}
325 		} else if (score == badness && reuseport) {
326 			matches++;
327 			if (((u64)hash * matches) >> 32 == 0)
328 				result = sk;
329 			hash = next_pseudo_random32(hash);
330 		}
331 	}
332 	/*
333 	 * if the nulls value we got at the end of this lookup is
334 	 * not the expected one, we must restart lookup.
335 	 * We probably met an item that was moved to another chain.
336 	 */
337 	if (get_nulls_value(node) != slot)
338 		goto begin;
339 
340 	if (result) {
341 		if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
342 			result = NULL;
343 		else if (unlikely(compute_score(result, net, hnum, saddr, sport,
344 					daddr, dport, dif) < badness)) {
345 			sock_put(result);
346 			goto begin;
347 		}
348 	}
349 	rcu_read_unlock();
350 	return result;
351 }
352 EXPORT_SYMBOL_GPL(__udp6_lib_lookup);
353 
354 static struct sock *__udp6_lib_lookup_skb(struct sk_buff *skb,
355 					  __be16 sport, __be16 dport,
356 					  struct udp_table *udptable)
357 {
358 	struct sock *sk;
359 	const struct ipv6hdr *iph = ipv6_hdr(skb);
360 
361 	if (unlikely(sk = skb_steal_sock(skb)))
362 		return sk;
363 	return __udp6_lib_lookup(dev_net(skb_dst(skb)->dev), &iph->saddr, sport,
364 				 &iph->daddr, dport, inet6_iif(skb),
365 				 udptable);
366 }
367 
368 struct sock *udp6_lib_lookup(struct net *net, const struct in6_addr *saddr, __be16 sport,
369 			     const struct in6_addr *daddr, __be16 dport, int dif)
370 {
371 	return __udp6_lib_lookup(net, saddr, sport, daddr, dport, dif, &udp_table);
372 }
373 EXPORT_SYMBOL_GPL(udp6_lib_lookup);
374 
375 
376 /*
377  * 	This should be easy, if there is something there we
378  * 	return it, otherwise we block.
379  */
380 
381 int udpv6_recvmsg(struct kiocb *iocb, struct sock *sk,
382 		  struct msghdr *msg, size_t len,
383 		  int noblock, int flags, int *addr_len)
384 {
385 	struct ipv6_pinfo *np = inet6_sk(sk);
386 	struct inet_sock *inet = inet_sk(sk);
387 	struct sk_buff *skb;
388 	unsigned int ulen, copied;
389 	int peeked, off = 0;
390 	int err;
391 	int is_udplite = IS_UDPLITE(sk);
392 	int is_udp4;
393 	bool slow;
394 
395 	if (flags & MSG_ERRQUEUE)
396 		return ipv6_recv_error(sk, msg, len, addr_len);
397 
398 	if (np->rxpmtu && np->rxopt.bits.rxpmtu)
399 		return ipv6_recv_rxpmtu(sk, msg, len, addr_len);
400 
401 try_again:
402 	skb = __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
403 				  &peeked, &off, &err);
404 	if (!skb)
405 		goto out;
406 
407 	ulen = skb->len - sizeof(struct udphdr);
408 	copied = len;
409 	if (copied > ulen)
410 		copied = ulen;
411 	else if (copied < ulen)
412 		msg->msg_flags |= MSG_TRUNC;
413 
414 	is_udp4 = (skb->protocol == htons(ETH_P_IP));
415 
416 	/*
417 	 * If checksum is needed at all, try to do it while copying the
418 	 * data.  If the data is truncated, or if we only want a partial
419 	 * coverage checksum (UDP-Lite), do it before the copy.
420 	 */
421 
422 	if (copied < ulen || UDP_SKB_CB(skb)->partial_cov) {
423 		if (udp_lib_checksum_complete(skb))
424 			goto csum_copy_err;
425 	}
426 
427 	if (skb_csum_unnecessary(skb))
428 		err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr),
429 					      msg->msg_iov, copied);
430 	else {
431 		err = skb_copy_and_csum_datagram_iovec(skb, sizeof(struct udphdr), msg->msg_iov);
432 		if (err == -EINVAL)
433 			goto csum_copy_err;
434 	}
435 	if (unlikely(err)) {
436 		trace_kfree_skb(skb, udpv6_recvmsg);
437 		if (!peeked) {
438 			atomic_inc(&sk->sk_drops);
439 			if (is_udp4)
440 				UDP_INC_STATS_USER(sock_net(sk),
441 						   UDP_MIB_INERRORS,
442 						   is_udplite);
443 			else
444 				UDP6_INC_STATS_USER(sock_net(sk),
445 						    UDP_MIB_INERRORS,
446 						    is_udplite);
447 		}
448 		goto out_free;
449 	}
450 	if (!peeked) {
451 		if (is_udp4)
452 			UDP_INC_STATS_USER(sock_net(sk),
453 					UDP_MIB_INDATAGRAMS, is_udplite);
454 		else
455 			UDP6_INC_STATS_USER(sock_net(sk),
456 					UDP_MIB_INDATAGRAMS, is_udplite);
457 	}
458 
459 	sock_recv_ts_and_drops(msg, sk, skb);
460 
461 	/* Copy the address. */
462 	if (msg->msg_name) {
463 		DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
464 		sin6->sin6_family = AF_INET6;
465 		sin6->sin6_port = udp_hdr(skb)->source;
466 		sin6->sin6_flowinfo = 0;
467 
468 		if (is_udp4) {
469 			ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
470 					       &sin6->sin6_addr);
471 			sin6->sin6_scope_id = 0;
472 		} else {
473 			sin6->sin6_addr = ipv6_hdr(skb)->saddr;
474 			sin6->sin6_scope_id =
475 				ipv6_iface_scope_id(&sin6->sin6_addr,
476 						    IP6CB(skb)->iif);
477 		}
478 		*addr_len = sizeof(*sin6);
479 	}
480 
481 	if (np->rxopt.all)
482 		ip6_datagram_recv_common_ctl(sk, msg, skb);
483 
484 	if (is_udp4) {
485 		if (inet->cmsg_flags)
486 			ip_cmsg_recv(msg, skb);
487 	} else {
488 		if (np->rxopt.all)
489 			ip6_datagram_recv_specific_ctl(sk, msg, skb);
490 	}
491 
492 	err = copied;
493 	if (flags & MSG_TRUNC)
494 		err = ulen;
495 
496 out_free:
497 	skb_free_datagram_locked(sk, skb);
498 out:
499 	return err;
500 
501 csum_copy_err:
502 	slow = lock_sock_fast(sk);
503 	if (!skb_kill_datagram(sk, skb, flags)) {
504 		if (is_udp4) {
505 			UDP_INC_STATS_USER(sock_net(sk),
506 					UDP_MIB_CSUMERRORS, is_udplite);
507 			UDP_INC_STATS_USER(sock_net(sk),
508 					UDP_MIB_INERRORS, is_udplite);
509 		} else {
510 			UDP6_INC_STATS_USER(sock_net(sk),
511 					UDP_MIB_CSUMERRORS, is_udplite);
512 			UDP6_INC_STATS_USER(sock_net(sk),
513 					UDP_MIB_INERRORS, is_udplite);
514 		}
515 	}
516 	unlock_sock_fast(sk, slow);
517 
518 	if (noblock)
519 		return -EAGAIN;
520 
521 	/* starting over for a new packet */
522 	msg->msg_flags &= ~MSG_TRUNC;
523 	goto try_again;
524 }
525 
526 void __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
527 		    u8 type, u8 code, int offset, __be32 info,
528 		    struct udp_table *udptable)
529 {
530 	struct ipv6_pinfo *np;
531 	const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
532 	const struct in6_addr *saddr = &hdr->saddr;
533 	const struct in6_addr *daddr = &hdr->daddr;
534 	struct udphdr *uh = (struct udphdr*)(skb->data+offset);
535 	struct sock *sk;
536 	int err;
537 
538 	sk = __udp6_lib_lookup(dev_net(skb->dev), daddr, uh->dest,
539 			       saddr, uh->source, inet6_iif(skb), udptable);
540 	if (sk == NULL)
541 		return;
542 
543 	if (type == ICMPV6_PKT_TOOBIG) {
544 		if (!ip6_sk_accept_pmtu(sk))
545 			goto out;
546 		ip6_sk_update_pmtu(skb, sk, info);
547 	}
548 	if (type == NDISC_REDIRECT) {
549 		ip6_sk_redirect(skb, sk);
550 		goto out;
551 	}
552 
553 	np = inet6_sk(sk);
554 
555 	if (!icmpv6_err_convert(type, code, &err) && !np->recverr)
556 		goto out;
557 
558 	if (sk->sk_state != TCP_ESTABLISHED && !np->recverr)
559 		goto out;
560 
561 	if (np->recverr)
562 		ipv6_icmp_error(sk, skb, err, uh->dest, ntohl(info), (u8 *)(uh+1));
563 
564 	sk->sk_err = err;
565 	sk->sk_error_report(sk);
566 out:
567 	sock_put(sk);
568 }
569 
570 static int __udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
571 {
572 	int rc;
573 
574 	if (!ipv6_addr_any(&sk->sk_v6_daddr)) {
575 		sock_rps_save_rxhash(sk, skb);
576 		sk_mark_napi_id(sk, skb);
577 	}
578 
579 	rc = sock_queue_rcv_skb(sk, skb);
580 	if (rc < 0) {
581 		int is_udplite = IS_UDPLITE(sk);
582 
583 		/* Note that an ENOMEM error is charged twice */
584 		if (rc == -ENOMEM)
585 			UDP6_INC_STATS_BH(sock_net(sk),
586 					UDP_MIB_RCVBUFERRORS, is_udplite);
587 		UDP6_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
588 		kfree_skb(skb);
589 		return -1;
590 	}
591 	return 0;
592 }
593 
594 static __inline__ void udpv6_err(struct sk_buff *skb,
595 				 struct inet6_skb_parm *opt, u8 type,
596 				 u8 code, int offset, __be32 info     )
597 {
598 	__udp6_lib_err(skb, opt, type, code, offset, info, &udp_table);
599 }
600 
601 static struct static_key udpv6_encap_needed __read_mostly;
602 void udpv6_encap_enable(void)
603 {
604 	if (!static_key_enabled(&udpv6_encap_needed))
605 		static_key_slow_inc(&udpv6_encap_needed);
606 }
607 EXPORT_SYMBOL(udpv6_encap_enable);
608 
609 int udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
610 {
611 	struct udp_sock *up = udp_sk(sk);
612 	int rc;
613 	int is_udplite = IS_UDPLITE(sk);
614 
615 	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
616 		goto drop;
617 
618 	if (static_key_false(&udpv6_encap_needed) && up->encap_type) {
619 		int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);
620 
621 		/*
622 		 * This is an encapsulation socket so pass the skb to
623 		 * the socket's udp_encap_rcv() hook. Otherwise, just
624 		 * fall through and pass this up the UDP socket.
625 		 * up->encap_rcv() returns the following value:
626 		 * =0 if skb was successfully passed to the encap
627 		 *    handler or was discarded by it.
628 		 * >0 if skb should be passed on to UDP.
629 		 * <0 if skb should be resubmitted as proto -N
630 		 */
631 
632 		/* if we're overly short, let UDP handle it */
633 		encap_rcv = ACCESS_ONCE(up->encap_rcv);
634 		if (skb->len > sizeof(struct udphdr) && encap_rcv != NULL) {
635 			int ret;
636 
637 			/* Verify checksum before giving to encap */
638 			if (udp_lib_checksum_complete(skb))
639 				goto csum_error;
640 
641 			ret = encap_rcv(sk, skb);
642 			if (ret <= 0) {
643 				UDP_INC_STATS_BH(sock_net(sk),
644 						 UDP_MIB_INDATAGRAMS,
645 						 is_udplite);
646 				return -ret;
647 			}
648 		}
649 
650 		/* FALLTHROUGH -- it's a UDP Packet */
651 	}
652 
653 	/*
654 	 * UDP-Lite specific tests, ignored on UDP sockets (see net/ipv4/udp.c).
655 	 */
656 	if ((is_udplite & UDPLITE_RECV_CC)  &&  UDP_SKB_CB(skb)->partial_cov) {
657 
658 		if (up->pcrlen == 0) {          /* full coverage was set  */
659 			LIMIT_NETDEBUG(KERN_WARNING "UDPLITE6: partial coverage"
660 				" %d while full coverage %d requested\n",
661 				UDP_SKB_CB(skb)->cscov, skb->len);
662 			goto drop;
663 		}
664 		if (UDP_SKB_CB(skb)->cscov  <  up->pcrlen) {
665 			LIMIT_NETDEBUG(KERN_WARNING "UDPLITE6: coverage %d "
666 						    "too small, need min %d\n",
667 				       UDP_SKB_CB(skb)->cscov, up->pcrlen);
668 			goto drop;
669 		}
670 	}
671 
672 	if (rcu_access_pointer(sk->sk_filter)) {
673 		if (udp_lib_checksum_complete(skb))
674 			goto csum_error;
675 	}
676 
677 	if (sk_rcvqueues_full(sk, skb, sk->sk_rcvbuf))
678 		goto drop;
679 
680 	skb_dst_drop(skb);
681 
682 	bh_lock_sock(sk);
683 	rc = 0;
684 	if (!sock_owned_by_user(sk))
685 		rc = __udpv6_queue_rcv_skb(sk, skb);
686 	else if (sk_add_backlog(sk, skb, sk->sk_rcvbuf)) {
687 		bh_unlock_sock(sk);
688 		goto drop;
689 	}
690 	bh_unlock_sock(sk);
691 
692 	return rc;
693 csum_error:
694 	UDP6_INC_STATS_BH(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
695 drop:
696 	UDP6_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
697 	atomic_inc(&sk->sk_drops);
698 	kfree_skb(skb);
699 	return -1;
700 }
701 
702 static struct sock *udp_v6_mcast_next(struct net *net, struct sock *sk,
703 				      __be16 loc_port, const struct in6_addr *loc_addr,
704 				      __be16 rmt_port, const struct in6_addr *rmt_addr,
705 				      int dif)
706 {
707 	struct hlist_nulls_node *node;
708 	unsigned short num = ntohs(loc_port);
709 
710 	sk_nulls_for_each_from(sk, node) {
711 		struct inet_sock *inet = inet_sk(sk);
712 
713 		if (!net_eq(sock_net(sk), net))
714 			continue;
715 
716 		if (udp_sk(sk)->udp_port_hash == num &&
717 		    sk->sk_family == PF_INET6) {
718 			if (inet->inet_dport) {
719 				if (inet->inet_dport != rmt_port)
720 					continue;
721 			}
722 			if (!ipv6_addr_any(&sk->sk_v6_daddr) &&
723 			    !ipv6_addr_equal(&sk->sk_v6_daddr, rmt_addr))
724 				continue;
725 
726 			if (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif)
727 				continue;
728 
729 			if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr)) {
730 				if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, loc_addr))
731 					continue;
732 			}
733 			if (!inet6_mc_check(sk, loc_addr, rmt_addr))
734 				continue;
735 			return sk;
736 		}
737 	}
738 	return NULL;
739 }
740 
741 static void flush_stack(struct sock **stack, unsigned int count,
742 			struct sk_buff *skb, unsigned int final)
743 {
744 	struct sk_buff *skb1 = NULL;
745 	struct sock *sk;
746 	unsigned int i;
747 
748 	for (i = 0; i < count; i++) {
749 		sk = stack[i];
750 		if (likely(skb1 == NULL))
751 			skb1 = (i == final) ? skb : skb_clone(skb, GFP_ATOMIC);
752 		if (!skb1) {
753 			atomic_inc(&sk->sk_drops);
754 			UDP6_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
755 					  IS_UDPLITE(sk));
756 			UDP6_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS,
757 					  IS_UDPLITE(sk));
758 		}
759 
760 		if (skb1 && udpv6_queue_rcv_skb(sk, skb1) <= 0)
761 			skb1 = NULL;
762 	}
763 	if (unlikely(skb1))
764 		kfree_skb(skb1);
765 }
766 
767 static void udp6_csum_zero_error(struct sk_buff *skb)
768 {
769 	/* RFC 2460 section 8.1 says that we SHOULD log
770 	 * this error. Well, it is reasonable.
771 	 */
772 	LIMIT_NETDEBUG(KERN_INFO "IPv6: udp checksum is 0 for [%pI6c]:%u->[%pI6c]:%u\n",
773 		       &ipv6_hdr(skb)->saddr, ntohs(udp_hdr(skb)->source),
774 		       &ipv6_hdr(skb)->daddr, ntohs(udp_hdr(skb)->dest));
775 }
776 
777 /*
778  * Note: called only from the BH handler context,
779  * so we don't need to lock the hashes.
780  */
781 static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
782 		const struct in6_addr *saddr, const struct in6_addr *daddr,
783 		struct udp_table *udptable)
784 {
785 	struct sock *sk, *stack[256 / sizeof(struct sock *)];
786 	const struct udphdr *uh = udp_hdr(skb);
787 	struct udp_hslot *hslot = udp_hashslot(udptable, net, ntohs(uh->dest));
788 	int dif;
789 	unsigned int i, count = 0;
790 
791 	spin_lock(&hslot->lock);
792 	sk = sk_nulls_head(&hslot->head);
793 	dif = inet6_iif(skb);
794 	sk = udp_v6_mcast_next(net, sk, uh->dest, daddr, uh->source, saddr, dif);
795 	while (sk) {
796 		/* If zero checksum and no_check is not on for
797 		 * the socket then skip it.
798 		 */
799 		if (uh->check || udp_sk(sk)->no_check6_rx)
800 			stack[count++] = sk;
801 
802 		sk = udp_v6_mcast_next(net, sk_nulls_next(sk), uh->dest, daddr,
803 				       uh->source, saddr, dif);
804 		if (unlikely(count == ARRAY_SIZE(stack))) {
805 			if (!sk)
806 				break;
807 			flush_stack(stack, count, skb, ~0);
808 			count = 0;
809 		}
810 	}
811 	/*
812 	 * before releasing the lock, we must take reference on sockets
813 	 */
814 	for (i = 0; i < count; i++)
815 		sock_hold(stack[i]);
816 
817 	spin_unlock(&hslot->lock);
818 
819 	if (count) {
820 		flush_stack(stack, count, skb, count - 1);
821 
822 		for (i = 0; i < count; i++)
823 			sock_put(stack[i]);
824 	} else {
825 		kfree_skb(skb);
826 	}
827 	return 0;
828 }
829 
830 int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
831 		   int proto)
832 {
833 	struct net *net = dev_net(skb->dev);
834 	struct sock *sk;
835 	struct udphdr *uh;
836 	const struct in6_addr *saddr, *daddr;
837 	u32 ulen = 0;
838 
839 	if (!pskb_may_pull(skb, sizeof(struct udphdr)))
840 		goto discard;
841 
842 	saddr = &ipv6_hdr(skb)->saddr;
843 	daddr = &ipv6_hdr(skb)->daddr;
844 	uh = udp_hdr(skb);
845 
846 	ulen = ntohs(uh->len);
847 	if (ulen > skb->len)
848 		goto short_packet;
849 
850 	if (proto == IPPROTO_UDP) {
851 		/* UDP validates ulen. */
852 
853 		/* Check for jumbo payload */
854 		if (ulen == 0)
855 			ulen = skb->len;
856 
857 		if (ulen < sizeof(*uh))
858 			goto short_packet;
859 
860 		if (ulen < skb->len) {
861 			if (pskb_trim_rcsum(skb, ulen))
862 				goto short_packet;
863 			saddr = &ipv6_hdr(skb)->saddr;
864 			daddr = &ipv6_hdr(skb)->daddr;
865 			uh = udp_hdr(skb);
866 		}
867 	}
868 
869 	if (udp6_csum_init(skb, uh, proto))
870 		goto csum_error;
871 
872 	/*
873 	 *	Multicast receive code
874 	 */
875 	if (ipv6_addr_is_multicast(daddr))
876 		return __udp6_lib_mcast_deliver(net, skb,
877 				saddr, daddr, udptable);
878 
879 	/* Unicast */
880 
881 	/*
882 	 * check socket cache ... must talk to Alan about his plans
883 	 * for sock caches... i'll skip this for now.
884 	 */
885 	sk = __udp6_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
886 	if (sk != NULL) {
887 		int ret;
888 
889 		if (!uh->check && !udp_sk(sk)->no_check6_rx) {
890 			sock_put(sk);
891 			udp6_csum_zero_error(skb);
892 			goto csum_error;
893 		}
894 
895 		ret = udpv6_queue_rcv_skb(sk, skb);
896 		sock_put(sk);
897 
898 		/* a return value > 0 means to resubmit the input, but
899 		 * it wants the return to be -protocol, or 0
900 		 */
901 		if (ret > 0)
902 			return -ret;
903 
904 		return 0;
905 	}
906 
907 	if (!uh->check) {
908 		udp6_csum_zero_error(skb);
909 		goto csum_error;
910 	}
911 
912 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
913 		goto discard;
914 
915 	if (udp_lib_checksum_complete(skb))
916 		goto csum_error;
917 
918 	UDP6_INC_STATS_BH(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
919 	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
920 
921 	kfree_skb(skb);
922 	return 0;
923 
924 short_packet:
925 	LIMIT_NETDEBUG(KERN_DEBUG "UDP%sv6: short packet: From [%pI6c]:%u %d/%d to [%pI6c]:%u\n",
926 		       proto == IPPROTO_UDPLITE ? "-Lite" : "",
927 		       saddr,
928 		       ntohs(uh->source),
929 		       ulen,
930 		       skb->len,
931 		       daddr,
932 		       ntohs(uh->dest));
933 	goto discard;
934 csum_error:
935 	UDP6_INC_STATS_BH(net, UDP_MIB_CSUMERRORS, proto == IPPROTO_UDPLITE);
936 discard:
937 	UDP6_INC_STATS_BH(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
938 	kfree_skb(skb);
939 	return 0;
940 }
941 
942 static __inline__ int udpv6_rcv(struct sk_buff *skb)
943 {
944 	return __udp6_lib_rcv(skb, &udp_table, IPPROTO_UDP);
945 }
946 
947 /*
948  * Throw away all pending data and cancel the corking. Socket is locked.
949  */
950 static void udp_v6_flush_pending_frames(struct sock *sk)
951 {
952 	struct udp_sock *up = udp_sk(sk);
953 
954 	if (up->pending == AF_INET)
955 		udp_flush_pending_frames(sk);
956 	else if (up->pending) {
957 		up->len = 0;
958 		up->pending = 0;
959 		ip6_flush_pending_frames(sk);
960 	}
961 }
962 
963 /**
964  * 	udp6_hwcsum_outgoing  -  handle outgoing HW checksumming
965  * 	@sk: 	socket we are sending on
966  * 	@skb: 	sk_buff containing the filled-in UDP header
967  * 	        (checksum field must be zeroed out)
968  */
969 static void udp6_hwcsum_outgoing(struct sock *sk, struct sk_buff *skb,
970 				 const struct in6_addr *saddr,
971 				 const struct in6_addr *daddr, int len)
972 {
973 	unsigned int offset;
974 	struct udphdr *uh = udp_hdr(skb);
975 	__wsum csum = 0;
976 
977 	if (skb_queue_len(&sk->sk_write_queue) == 1) {
978 		/* Only one fragment on the socket.  */
979 		skb->csum_start = skb_transport_header(skb) - skb->head;
980 		skb->csum_offset = offsetof(struct udphdr, check);
981 		uh->check = ~csum_ipv6_magic(saddr, daddr, len, IPPROTO_UDP, 0);
982 	} else {
983 		/*
984 		 * HW-checksum won't work as there are two or more
985 		 * fragments on the socket so that all csums of sk_buffs
986 		 * should be together
987 		 */
988 		offset = skb_transport_offset(skb);
989 		skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
990 
991 		skb->ip_summed = CHECKSUM_NONE;
992 
993 		skb_queue_walk(&sk->sk_write_queue, skb) {
994 			csum = csum_add(csum, skb->csum);
995 		}
996 
997 		uh->check = csum_ipv6_magic(saddr, daddr, len, IPPROTO_UDP,
998 					    csum);
999 		if (uh->check == 0)
1000 			uh->check = CSUM_MANGLED_0;
1001 	}
1002 }
1003 
1004 /*
1005  *	Sending
1006  */
1007 
1008 static int udp_v6_push_pending_frames(struct sock *sk)
1009 {
1010 	struct sk_buff *skb;
1011 	struct udphdr *uh;
1012 	struct udp_sock  *up = udp_sk(sk);
1013 	struct inet_sock *inet = inet_sk(sk);
1014 	struct flowi6 *fl6;
1015 	int err = 0;
1016 	int is_udplite = IS_UDPLITE(sk);
1017 	__wsum csum = 0;
1018 
1019 	if (up->pending == AF_INET)
1020 		return udp_push_pending_frames(sk);
1021 
1022 	fl6 = &inet->cork.fl.u.ip6;
1023 
1024 	/* Grab the skbuff where UDP header space exists. */
1025 	if ((skb = skb_peek(&sk->sk_write_queue)) == NULL)
1026 		goto out;
1027 
1028 	/*
1029 	 * Create a UDP header
1030 	 */
1031 	uh = udp_hdr(skb);
1032 	uh->source = fl6->fl6_sport;
1033 	uh->dest = fl6->fl6_dport;
1034 	uh->len = htons(up->len);
1035 	uh->check = 0;
1036 
1037 	if (is_udplite)
1038 		csum = udplite_csum_outgoing(sk, skb);
1039 	else if (up->no_check6_tx) {   /* UDP csum disabled */
1040 		skb->ip_summed = CHECKSUM_NONE;
1041 		goto send;
1042 	} else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
1043 		udp6_hwcsum_outgoing(sk, skb, &fl6->saddr, &fl6->daddr,
1044 				     up->len);
1045 		goto send;
1046 	} else
1047 		csum = udp_csum_outgoing(sk, skb);
1048 
1049 	/* add protocol-dependent pseudo-header */
1050 	uh->check = csum_ipv6_magic(&fl6->saddr, &fl6->daddr,
1051 				    up->len, fl6->flowi6_proto, csum);
1052 	if (uh->check == 0)
1053 		uh->check = CSUM_MANGLED_0;
1054 
1055 send:
1056 	err = ip6_push_pending_frames(sk);
1057 	if (err) {
1058 		if (err == -ENOBUFS && !inet6_sk(sk)->recverr) {
1059 			UDP6_INC_STATS_USER(sock_net(sk),
1060 					    UDP_MIB_SNDBUFERRORS, is_udplite);
1061 			err = 0;
1062 		}
1063 	} else
1064 		UDP6_INC_STATS_USER(sock_net(sk),
1065 				    UDP_MIB_OUTDATAGRAMS, is_udplite);
1066 out:
1067 	up->len = 0;
1068 	up->pending = 0;
1069 	return err;
1070 }
1071 
1072 int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk,
1073 		  struct msghdr *msg, size_t len)
1074 {
1075 	struct ipv6_txoptions opt_space;
1076 	struct udp_sock *up = udp_sk(sk);
1077 	struct inet_sock *inet = inet_sk(sk);
1078 	struct ipv6_pinfo *np = inet6_sk(sk);
1079 	DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
1080 	struct in6_addr *daddr, *final_p, final;
1081 	struct ipv6_txoptions *opt = NULL;
1082 	struct ip6_flowlabel *flowlabel = NULL;
1083 	struct flowi6 fl6;
1084 	struct dst_entry *dst;
1085 	int addr_len = msg->msg_namelen;
1086 	int ulen = len;
1087 	int hlimit = -1;
1088 	int tclass = -1;
1089 	int dontfrag = -1;
1090 	int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
1091 	int err;
1092 	int connected = 0;
1093 	int is_udplite = IS_UDPLITE(sk);
1094 	int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
1095 
1096 	/* destination address check */
1097 	if (sin6) {
1098 		if (addr_len < offsetof(struct sockaddr, sa_data))
1099 			return -EINVAL;
1100 
1101 		switch (sin6->sin6_family) {
1102 		case AF_INET6:
1103 			if (addr_len < SIN6_LEN_RFC2133)
1104 				return -EINVAL;
1105 			daddr = &sin6->sin6_addr;
1106 			break;
1107 		case AF_INET:
1108 			goto do_udp_sendmsg;
1109 		case AF_UNSPEC:
1110 			msg->msg_name = sin6 = NULL;
1111 			msg->msg_namelen = addr_len = 0;
1112 			daddr = NULL;
1113 			break;
1114 		default:
1115 			return -EINVAL;
1116 		}
1117 	} else if (!up->pending) {
1118 		if (sk->sk_state != TCP_ESTABLISHED)
1119 			return -EDESTADDRREQ;
1120 		daddr = &sk->sk_v6_daddr;
1121 	} else
1122 		daddr = NULL;
1123 
1124 	if (daddr) {
1125 		if (ipv6_addr_v4mapped(daddr)) {
1126 			struct sockaddr_in sin;
1127 			sin.sin_family = AF_INET;
1128 			sin.sin_port = sin6 ? sin6->sin6_port : inet->inet_dport;
1129 			sin.sin_addr.s_addr = daddr->s6_addr32[3];
1130 			msg->msg_name = &sin;
1131 			msg->msg_namelen = sizeof(sin);
1132 do_udp_sendmsg:
1133 			if (__ipv6_only_sock(sk))
1134 				return -ENETUNREACH;
1135 			return udp_sendmsg(iocb, sk, msg, len);
1136 		}
1137 	}
1138 
1139 	if (up->pending == AF_INET)
1140 		return udp_sendmsg(iocb, sk, msg, len);
1141 
1142 	/* Rough check on arithmetic overflow,
1143 	   better check is made in ip6_append_data().
1144 	   */
1145 	if (len > INT_MAX - sizeof(struct udphdr))
1146 		return -EMSGSIZE;
1147 
1148 	if (up->pending) {
1149 		/*
1150 		 * There are pending frames.
1151 		 * The socket lock must be held while it's corked.
1152 		 */
1153 		lock_sock(sk);
1154 		if (likely(up->pending)) {
1155 			if (unlikely(up->pending != AF_INET6)) {
1156 				release_sock(sk);
1157 				return -EAFNOSUPPORT;
1158 			}
1159 			dst = NULL;
1160 			goto do_append_data;
1161 		}
1162 		release_sock(sk);
1163 	}
1164 	ulen += sizeof(struct udphdr);
1165 
1166 	memset(&fl6, 0, sizeof(fl6));
1167 
1168 	if (sin6) {
1169 		if (sin6->sin6_port == 0)
1170 			return -EINVAL;
1171 
1172 		fl6.fl6_dport = sin6->sin6_port;
1173 		daddr = &sin6->sin6_addr;
1174 
1175 		if (np->sndflow) {
1176 			fl6.flowlabel = sin6->sin6_flowinfo&IPV6_FLOWINFO_MASK;
1177 			if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
1178 				flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
1179 				if (flowlabel == NULL)
1180 					return -EINVAL;
1181 			}
1182 		}
1183 
1184 		/*
1185 		 * Otherwise it will be difficult to maintain
1186 		 * sk->sk_dst_cache.
1187 		 */
1188 		if (sk->sk_state == TCP_ESTABLISHED &&
1189 		    ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
1190 			daddr = &sk->sk_v6_daddr;
1191 
1192 		if (addr_len >= sizeof(struct sockaddr_in6) &&
1193 		    sin6->sin6_scope_id &&
1194 		    __ipv6_addr_needs_scope_id(__ipv6_addr_type(daddr)))
1195 			fl6.flowi6_oif = sin6->sin6_scope_id;
1196 	} else {
1197 		if (sk->sk_state != TCP_ESTABLISHED)
1198 			return -EDESTADDRREQ;
1199 
1200 		fl6.fl6_dport = inet->inet_dport;
1201 		daddr = &sk->sk_v6_daddr;
1202 		fl6.flowlabel = np->flow_label;
1203 		connected = 1;
1204 	}
1205 
1206 	if (!fl6.flowi6_oif)
1207 		fl6.flowi6_oif = sk->sk_bound_dev_if;
1208 
1209 	if (!fl6.flowi6_oif)
1210 		fl6.flowi6_oif = np->sticky_pktinfo.ipi6_ifindex;
1211 
1212 	fl6.flowi6_mark = sk->sk_mark;
1213 
1214 	if (msg->msg_controllen) {
1215 		opt = &opt_space;
1216 		memset(opt, 0, sizeof(struct ipv6_txoptions));
1217 		opt->tot_len = sizeof(*opt);
1218 
1219 		err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, opt,
1220 					    &hlimit, &tclass, &dontfrag);
1221 		if (err < 0) {
1222 			fl6_sock_release(flowlabel);
1223 			return err;
1224 		}
1225 		if ((fl6.flowlabel&IPV6_FLOWLABEL_MASK) && !flowlabel) {
1226 			flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
1227 			if (flowlabel == NULL)
1228 				return -EINVAL;
1229 		}
1230 		if (!(opt->opt_nflen|opt->opt_flen))
1231 			opt = NULL;
1232 		connected = 0;
1233 	}
1234 	if (opt == NULL)
1235 		opt = np->opt;
1236 	if (flowlabel)
1237 		opt = fl6_merge_options(&opt_space, flowlabel, opt);
1238 	opt = ipv6_fixup_options(&opt_space, opt);
1239 
1240 	fl6.flowi6_proto = sk->sk_protocol;
1241 	if (!ipv6_addr_any(daddr))
1242 		fl6.daddr = *daddr;
1243 	else
1244 		fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
1245 	if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
1246 		fl6.saddr = np->saddr;
1247 	fl6.fl6_sport = inet->inet_sport;
1248 
1249 	final_p = fl6_update_dst(&fl6, opt, &final);
1250 	if (final_p)
1251 		connected = 0;
1252 
1253 	if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) {
1254 		fl6.flowi6_oif = np->mcast_oif;
1255 		connected = 0;
1256 	} else if (!fl6.flowi6_oif)
1257 		fl6.flowi6_oif = np->ucast_oif;
1258 
1259 	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
1260 
1261 	dst = ip6_sk_dst_lookup_flow(sk, &fl6, final_p);
1262 	if (IS_ERR(dst)) {
1263 		err = PTR_ERR(dst);
1264 		dst = NULL;
1265 		goto out;
1266 	}
1267 
1268 	if (hlimit < 0)
1269 		hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
1270 
1271 	if (tclass < 0)
1272 		tclass = np->tclass;
1273 
1274 	if (msg->msg_flags&MSG_CONFIRM)
1275 		goto do_confirm;
1276 back_from_confirm:
1277 
1278 	lock_sock(sk);
1279 	if (unlikely(up->pending)) {
1280 		/* The socket is already corked while preparing it. */
1281 		/* ... which is an evident application bug. --ANK */
1282 		release_sock(sk);
1283 
1284 		LIMIT_NETDEBUG(KERN_DEBUG "udp cork app bug 2\n");
1285 		err = -EINVAL;
1286 		goto out;
1287 	}
1288 
1289 	up->pending = AF_INET6;
1290 
1291 do_append_data:
1292 	if (dontfrag < 0)
1293 		dontfrag = np->dontfrag;
1294 	up->len += ulen;
1295 	getfrag  =  is_udplite ?  udplite_getfrag : ip_generic_getfrag;
1296 	err = ip6_append_data(sk, getfrag, msg->msg_iov, ulen,
1297 		sizeof(struct udphdr), hlimit, tclass, opt, &fl6,
1298 		(struct rt6_info*)dst,
1299 		corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags, dontfrag);
1300 	if (err)
1301 		udp_v6_flush_pending_frames(sk);
1302 	else if (!corkreq)
1303 		err = udp_v6_push_pending_frames(sk);
1304 	else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
1305 		up->pending = 0;
1306 
1307 	if (dst) {
1308 		if (connected) {
1309 			ip6_dst_store(sk, dst,
1310 				      ipv6_addr_equal(&fl6.daddr, &sk->sk_v6_daddr) ?
1311 				      &sk->sk_v6_daddr : NULL,
1312 #ifdef CONFIG_IPV6_SUBTREES
1313 				      ipv6_addr_equal(&fl6.saddr, &np->saddr) ?
1314 				      &np->saddr :
1315 #endif
1316 				      NULL);
1317 		} else {
1318 			dst_release(dst);
1319 		}
1320 		dst = NULL;
1321 	}
1322 
1323 	if (err > 0)
1324 		err = np->recverr ? net_xmit_errno(err) : 0;
1325 	release_sock(sk);
1326 out:
1327 	dst_release(dst);
1328 	fl6_sock_release(flowlabel);
1329 	if (!err)
1330 		return len;
1331 	/*
1332 	 * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space.  Reporting
1333 	 * ENOBUFS might not be good (it's not tunable per se), but otherwise
1334 	 * we don't have a good statistic (IpOutDiscards but it can be too many
1335 	 * things).  We could add another new stat but at least for now that
1336 	 * seems like overkill.
1337 	 */
1338 	if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
1339 		UDP6_INC_STATS_USER(sock_net(sk),
1340 				UDP_MIB_SNDBUFERRORS, is_udplite);
1341 	}
1342 	return err;
1343 
1344 do_confirm:
1345 	dst_confirm(dst);
1346 	if (!(msg->msg_flags&MSG_PROBE) || len)
1347 		goto back_from_confirm;
1348 	err = 0;
1349 	goto out;
1350 }
1351 
1352 void udpv6_destroy_sock(struct sock *sk)
1353 {
1354 	struct udp_sock *up = udp_sk(sk);
1355 	lock_sock(sk);
1356 	udp_v6_flush_pending_frames(sk);
1357 	release_sock(sk);
1358 
1359 	if (static_key_false(&udpv6_encap_needed) && up->encap_type) {
1360 		void (*encap_destroy)(struct sock *sk);
1361 		encap_destroy = ACCESS_ONCE(up->encap_destroy);
1362 		if (encap_destroy)
1363 			encap_destroy(sk);
1364 	}
1365 
1366 	inet6_destroy_sock(sk);
1367 }
1368 
1369 /*
1370  *	Socket option code for UDP
1371  */
1372 int udpv6_setsockopt(struct sock *sk, int level, int optname,
1373 		     char __user *optval, unsigned int optlen)
1374 {
1375 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1376 		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
1377 					  udp_v6_push_pending_frames);
1378 	return ipv6_setsockopt(sk, level, optname, optval, optlen);
1379 }
1380 
1381 #ifdef CONFIG_COMPAT
1382 int compat_udpv6_setsockopt(struct sock *sk, int level, int optname,
1383 			    char __user *optval, unsigned int optlen)
1384 {
1385 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1386 		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
1387 					  udp_v6_push_pending_frames);
1388 	return compat_ipv6_setsockopt(sk, level, optname, optval, optlen);
1389 }
1390 #endif
1391 
1392 int udpv6_getsockopt(struct sock *sk, int level, int optname,
1393 		     char __user *optval, int __user *optlen)
1394 {
1395 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1396 		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
1397 	return ipv6_getsockopt(sk, level, optname, optval, optlen);
1398 }
1399 
1400 #ifdef CONFIG_COMPAT
1401 int compat_udpv6_getsockopt(struct sock *sk, int level, int optname,
1402 			    char __user *optval, int __user *optlen)
1403 {
1404 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1405 		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
1406 	return compat_ipv6_getsockopt(sk, level, optname, optval, optlen);
1407 }
1408 #endif
1409 
1410 static const struct inet6_protocol udpv6_protocol = {
1411 	.handler	=	udpv6_rcv,
1412 	.err_handler	=	udpv6_err,
1413 	.flags		=	INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1414 };
1415 
1416 /* ------------------------------------------------------------------------ */
1417 #ifdef CONFIG_PROC_FS
1418 int udp6_seq_show(struct seq_file *seq, void *v)
1419 {
1420 	if (v == SEQ_START_TOKEN) {
1421 		seq_puts(seq, IPV6_SEQ_DGRAM_HEADER);
1422 	} else {
1423 		int bucket = ((struct udp_iter_state *)seq->private)->bucket;
1424 		struct inet_sock *inet = inet_sk(v);
1425 		__u16 srcp = ntohs(inet->inet_sport);
1426 		__u16 destp = ntohs(inet->inet_dport);
1427 		ip6_dgram_sock_seq_show(seq, v, srcp, destp, bucket);
1428 	}
1429 	return 0;
1430 }
1431 
1432 static const struct file_operations udp6_afinfo_seq_fops = {
1433 	.owner    = THIS_MODULE,
1434 	.open     = udp_seq_open,
1435 	.read     = seq_read,
1436 	.llseek   = seq_lseek,
1437 	.release  = seq_release_net
1438 };
1439 
1440 static struct udp_seq_afinfo udp6_seq_afinfo = {
1441 	.name		= "udp6",
1442 	.family		= AF_INET6,
1443 	.udp_table	= &udp_table,
1444 	.seq_fops	= &udp6_afinfo_seq_fops,
1445 	.seq_ops	= {
1446 		.show		= udp6_seq_show,
1447 	},
1448 };
1449 
1450 int __net_init udp6_proc_init(struct net *net)
1451 {
1452 	return udp_proc_register(net, &udp6_seq_afinfo);
1453 }
1454 
1455 void udp6_proc_exit(struct net *net) {
1456 	udp_proc_unregister(net, &udp6_seq_afinfo);
1457 }
1458 #endif /* CONFIG_PROC_FS */
1459 
1460 void udp_v6_clear_sk(struct sock *sk, int size)
1461 {
1462 	struct inet_sock *inet = inet_sk(sk);
1463 
1464 	/* we do not want to clear pinet6 field, because of RCU lookups */
1465 	sk_prot_clear_portaddr_nulls(sk, offsetof(struct inet_sock, pinet6));
1466 
1467 	size -= offsetof(struct inet_sock, pinet6) + sizeof(inet->pinet6);
1468 	memset(&inet->pinet6 + 1, 0, size);
1469 }
1470 
1471 /* ------------------------------------------------------------------------ */
1472 
1473 struct proto udpv6_prot = {
1474 	.name		   = "UDPv6",
1475 	.owner		   = THIS_MODULE,
1476 	.close		   = udp_lib_close,
1477 	.connect	   = ip6_datagram_connect,
1478 	.disconnect	   = udp_disconnect,
1479 	.ioctl		   = udp_ioctl,
1480 	.destroy	   = udpv6_destroy_sock,
1481 	.setsockopt	   = udpv6_setsockopt,
1482 	.getsockopt	   = udpv6_getsockopt,
1483 	.sendmsg	   = udpv6_sendmsg,
1484 	.recvmsg	   = udpv6_recvmsg,
1485 	.backlog_rcv	   = __udpv6_queue_rcv_skb,
1486 	.hash		   = udp_lib_hash,
1487 	.unhash		   = udp_lib_unhash,
1488 	.rehash		   = udp_v6_rehash,
1489 	.get_port	   = udp_v6_get_port,
1490 	.memory_allocated  = &udp_memory_allocated,
1491 	.sysctl_mem	   = sysctl_udp_mem,
1492 	.sysctl_wmem	   = &sysctl_udp_wmem_min,
1493 	.sysctl_rmem	   = &sysctl_udp_rmem_min,
1494 	.obj_size	   = sizeof(struct udp6_sock),
1495 	.slab_flags	   = SLAB_DESTROY_BY_RCU,
1496 	.h.udp_table	   = &udp_table,
1497 #ifdef CONFIG_COMPAT
1498 	.compat_setsockopt = compat_udpv6_setsockopt,
1499 	.compat_getsockopt = compat_udpv6_getsockopt,
1500 #endif
1501 	.clear_sk	   = udp_v6_clear_sk,
1502 };
1503 
1504 static struct inet_protosw udpv6_protosw = {
1505 	.type =      SOCK_DGRAM,
1506 	.protocol =  IPPROTO_UDP,
1507 	.prot =      &udpv6_prot,
1508 	.ops =       &inet6_dgram_ops,
1509 	.flags =     INET_PROTOSW_PERMANENT,
1510 };
1511 
1512 
1513 int __init udpv6_init(void)
1514 {
1515 	int ret;
1516 
1517 	ret = inet6_add_protocol(&udpv6_protocol, IPPROTO_UDP);
1518 	if (ret)
1519 		goto out;
1520 
1521 	ret = inet6_register_protosw(&udpv6_protosw);
1522 	if (ret)
1523 		goto out_udpv6_protocol;
1524 out:
1525 	return ret;
1526 
1527 out_udpv6_protocol:
1528 	inet6_del_protocol(&udpv6_protocol, IPPROTO_UDP);
1529 	goto out;
1530 }
1531 
1532 void udpv6_exit(void)
1533 {
1534 	inet6_unregister_protosw(&udpv6_protosw);
1535 	inet6_del_protocol(&udpv6_protocol, IPPROTO_UDP);
1536 }
1537